I am getting so frustrated with my 16 month old ds. Whenever I ask him to do something (come to Mommy, put that down, etc.) he only does it once I get cross and my voice gets sharp (sometimes to the point of shouting). I don't want to shout at him, and I would like to give him the chance to do what I ask before making him do it (picking him up or taking something out of his hands). But it is driving me bonkers. It seems that I have to get cross at him about everything! Is this a phase?